RF cavity filters may be used in linear power amplifiers and radio equipment such as cellular base stations, among other things, to, for example, reduce undesired frequencies in an RF signal, or to delay an RF signal by a predetermined amount of time.
Many efforts to reduce the size of devices such as linear power amplifiers and other electronic modules utilizing high-power electronic components and/or RF cavity filters have focused upon increased integration of electronic components. Sophisticated thermal management techniques such as two-phase cooling, which allow further abatement of device sizes, have often been employed to dissipate the heat generated by integrated electronics.
For example, evaporative spray cooling, described in detail in U.S. Pat. No. 5,220,804 to Tilton et al. which is incorporated herein by reference, is a preferred method of heat removal in many electronics applications and its use typically enables product and/or packaging sizes to be significantly reduced.
Generally, however, because RF cavity filters require a specific finite volume (occupied by a dielectric material such as air or oil) to provide a desired frequency response, reduction of product size resulting from electronic integration and advanced thermal management has not significantly impacted the sizes of RF cavity filters.
There is therefore a need for an improved RF filter, and for apparatuses and methods for cooling heat sources using RF filters which will result in reduced sizes of devices incorporating such apparatuses and methods.